The classic UI uses ExtJS to create widgets that provide the look-and-feel. Due to the nature of these widgets there are some differences between how components interact with the classic UI and the touch-optimized UI.

However, many aspects of a component are common to both UIs so you must read Components - the Basics before starting on the specifics of the classic UI on this page..

Note:

Although both the HTML Template Language (HTL) and JSP can be used for developing components for the classic UI, we will illustrate development with JSP on this page. This is solely due to the history of using JSP with the classic UI.

Structure

The basic structure of a component is covered on the page AEM Components - the Basics. This section covers both the touch-optimized and classic UIs - even if you do not need to use the settings for the touch-optimized UI in your new component it can help to be aware of them when inheriting from existing components.

JSP Scripts

JSP Scripts or Servlets can be used to render components. According to the request processing rules of Sling the name for the default script is:

<componentname>.jsp

global.jsp

The JSP script file global.jsp is used to provide quick access to specific objects (i.e. to access content) to any JSP script file used to render a component.

Therefore global.jsp should be included in every component rendering JSP script where one or more of the objects provided in global.jsp are used.

The location of the default global.jsp is:

/libs/foundation/global.jsp

Note:

The path /libs/wcm/global.jsp, which was used by the versions CQ 5.3 and earlier, is now obsolete.

Function of global.jsp, used APIs and Taglibs

The following lists the most important objects provided from the default global.jsp:

Accessing Content

There are three methods to access content in AEM WCM:

Via the properties object introduced in global.jsp:
The properties object is an instance of a ValueMap (see Sling API) and contains all properties of the current resource.
Example: String pageTitle = properties.get("jcr:title", "no title"); used in the rendering script of a page component.
Example: String paragraphTitle = properties.get("jcr:title", "no title"); used in the rendering script of a standard paragraph component.

Via the currentPage object introduced in global.jsp:
The currentPage object is an instance of a page (see AEM API). The page class provides some methods to access content.
Example: String pageTitle = currentPage.getTitle();

Via currentNode object introduced in global.jsp:
The currentNode object is an instance of a node (see JCR API). The properties of a node can be accessed by the getProperty() method.
Example: String pageTitle = currentNode.getProperty("jcr:title");

JSP Tag Libraries

The CQ and Sling tag libraries give you access to specific functions for use in the JSP script of your templates and components.

Using Client-Side HTML Libraries

Modern websites rely heavily on client-side processing driven by complex JavaScript and CSS code. Organizing and optimizing the serving of this code can be a complicated issue.

To help deal with this issue, AEM provides Client-side Library Folders, which allow you to store your client-side code in the repository, organize it into categories and define when and how each category of code is to be served to the client. The client-side library system then takes care of producing the correct links in your final web page to load the correct code.

Dialog

Configuring the Edit Behaviour

You can configure the edit behavior of a component; this includes attributes such as actions available for the component, characteristics of the inplace editor and the listeners related to events on the component. The configuration is common to both the touch-optimized and classic UI, albeit with certain, specific differences.

Develop a new component (adapt existing component)

To develop new components for AEM based on existing component you can copy the component, create a javascript file for the new component and store it in a location accessible to AEM (see also Customizing Components and Other Elements):

Using CRXDE Lite, create a new component folder in:

/apps/<myProject>/components/<myComponent>

Recreate the node structure as in libs, then copy the definition of an existing component, such as the Text component. For example, to customize the Text component copy:

from /libs/foundation/components/text

to /apps/myProject/components/text

Modify the jcr:title to reflect its new name.

Open the new component folder and make the changes you require; also, delete any extraneous information in the folder.

You can make changes such as:

adding a new field in the dialog box

cq:dialog - dialog for the touch-optimized UI

dialog - dialog for the classic UI

replacing the .jsp file (name it after your new component)

or completely reworking the entire component if you want

For example, if you take a copy of the standard Text component, you can add an additional field to the dialog box, then update the .jsp to process the input made there.

In AEM WCM, open a page in your web site and insert a new paragraph of the type you just created to make sure the component is working properly.

Note:

To see timing statistics for page loading, you can use Ctrl-Shift-U - with ?debugClientLibs=true set in the URL.

Adding a new component to the paragraph system (design mode)

After the component has been developed, you add it to the paragraph system, which enables authors to select and use the component when editing a page.

Access a page within your authoring environment that uses the paragraph system; for example <contentPath>/Test.html.

Switch to Design mode by either:

adding ?wcmmode=design to the end of the URL and accessing again; for example:<contextPath>/ Test.html?wcmmode=design

clicking Design in Sidekick

You are now in design mode and can edit the paragraph system.

Click Edit.

A list of components belonging to the paragraph system are shown. Your new component is also listed.

The components can be activated (or deactivated) to determine which are offered to the author when editing a page.

Activate your component, then return to normal edit mode to confirm that it is available for use.

Extending the Text and Image Component - An Example

This section provides an example on how to extend the widely used text and image standard component with a configurable image placement feature.

The extension to the text and image component allows editors to use all the existing functionality of the component plus have an extra option to specify the placement of the image either:

on the left-hand side of the text (current behavior and the new default)

as well as on the right-hand side

After extending this component, you can configure the image placement through the component's dialog box.

The following techniques are described in this exercise:

Copying existing component node and modifying its metadata

Modifying the component's dialog, including inheritance of widgets from parent dialog boxes

Modifying the component's script to implement the new functionality

Note:

This example is targeted at the classic UI.

Extending the existing textimage component

To create the new component, we use the standard textimage component as a basis and modify it. We store the new component in the Geometrixx AEM WCM example application.

Copy the standard textimage component from /libs/foundation/components/textimage into the Geometrixx component folder, /apps/geometrixx/components, using textimage as the target node name. (Copy the component by navigating to the component, right-clicking and selecting Copy and browsing to the target directory.)

To keep this example simple, navigate to the component you copied and delete all the subnodes of the new textimage node except for the following ones:

Parent component for the new component (the standard textimage component)

Set sling:resourceSuperType to foundation/components/textimage

After this step, the component node looks like this:

Change the sling:resourceType property of the edit configuration node of the image (property: textimage/cq:editConfig/cq:dropTargets/image/parameters/sling:resourceType) to geometrixx/components/textimage.

This way, when an image is dropped to the component on the page, the sling:resourceType property of the extended textimage component is set to: geometrixx/components/textimage.

Modify the component's dialog box to include the new option. The new component inherits the parts of the dialog box that are the same as in the original. The only addition we make is to extend the Advanced tab, adding an Image Position dropdown list, with options Left and Right:

Leave the textimage/dialog properties unchanged.

Note how textimage/dialog/items has four subnodes, tab1 to tab4, representing the four tabs of the textimage dialog box.

For the first two tabs (tab1 and tab2):

Change xtype to cqinclude (to inherit from the standard component).

Add a path property with values /libs/foundation/components/textimage/dialog/items/tab1.infinity.json and /libs/foundation/components/textimage/dialog/items/tab2.infinity.json, respectively.

Remove all other properties or subnodes.

For tab3:

Leave the properties and subnodes without changes

Add a new field definition to tab3/items, node position of type cq:Widget

Set the following properties (of type String) for the new tab3/items/position node:

name: ./imagePosition

xtype: selection

fieldLabel: Image Position

type: select

Add subnode position/options of type cq:WidgetCollection to represent the two choices for image placement, and under it create two nodes, o1 and o2 of type nt:unstructured.

For node position/options/o1 set the properties: text to Left and value to left.

For node position/options/o2 set the properties: text to Right and value to right.

Delete tab4.

Image position is persisted in content as the imagePosition property of the node representing textimage paragraph. After these steps, the component dialog box looks like this:

Extend the component script, textimage.jsp, with extra handling of the new parameter:

4. Save the component to the repository. The component is ready to test.

Checking the new component

After the component has been developed, you can add it to the paragraph system, which enables authors to select and use the component when editing a page. These steps allow you to test the component.

Open a page in Geometrixx; for example, English / Company.

Switch to design mode by clicking Design in Sidekick.

Edit the paragraph system design by clicking Edit on the paragraph system in the middle of the page. A list of components, which can be placed in the paragraph system are shown, and it should include your newly developed component, Text Image (Extended) . Activate it for the paragraph system by selecting it and clicking OK .

Switch back to the editing mode.

Add the Text Image (Extended) paragraph to the paragraph system, initialize text and image with sample content. Save the changes.

Open the dialog of the text and image paragraph, and change the Image Position on the Advanced tab to Right , and click OK to save the changes.

The paragraph is rendered with the image on the right.

The component is now ready to use.

The component stores its content in a paragraph on the Company page.

Disable Upload Capability of the Image Component

To disable this capability, we use the standard image component as a basis and modify it. We store the new component in the Geometrixx example application.

Copy the standard image component from /libs/foundation/components/image into the Geometrixx component folder, /apps/geometrixx/components, using image as the target node name.

Edit the component metadata:

Set jcr:title to Image (Extended)

Navigate to /apps/geometrixx/components/image/dialog/items/image.

Add a new property:

Name: allowUpload

Type: String

Value: false

Click Save All. The component is ready to test.

Open a page in Geometrixx; for example, English / Company.

Switch to design mode and activate Image (Extended).

Switch back to the editing mode and add it to the paragraph system. On the next pictures, you can see the differences between the original image component and the one you just created.

Original image component:

Your new image component:

The component is now ready to use.

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